DENVER -- A large, fast-moving snowstorm closed sections of major highways on the Plains yesterday and was blamed for at least seven traffic deaths, while strong winds in Arkansas cut a 5-mile-long swath of damage.

The storms on the Plains knocked out power to more than 100,000 customers and dumped more than a foot of snow on the Upper Midwest. The seven deaths occurred on slippery Wisconsin roads.

Some residents in the southeastern Arkansas city of Dumas were unaccounted for after winds, and possibly a series of tornadoes, blew through and police were making a door-to-door search, authorities said.

The winds destroyed buildings and left several people injured. Emergency crews requested ambulances from a neighboring county.

A Fred's Dollar Store just south of Dumas was left in a tangle of twisted metal and crumbled concrete blocks, and an overturned tractor-trailer rested in its parking lot. A power substation was wrecked and electricity was out in the area.

Forecasters said the damage could have been done by a tornado or by straight-line winds that might have exceeded 70 miles per hour.

In Colorado, Interstate 70 was closed for about 200 miles in both directions from just east of Denver to Colby, Kan., because of blowing snow and slippery pavement, according to Colorado and Kansas highway officials.

Between Denver and the beginning of the I-70 closure, about 35 cars collided in a pileup during a whiteout yesterday morning on an icy section of the interstate. No major injuries were reported.

Several other highways also were closed in Wyoming and Nebraska.

The weather service reported wind gusts of 68 miles per hour in the Denver area.

"Basically there's zero visibility at this time," Barb Blue, a spokeswoman for the Kansas Department of Transportation, said around noon. But many roads reopened later yesterday, including most of Interstate 80 in Nebraska, of which more than 270 miles had been closed.

Power was knocked out to 100,000 customers, primarily in Iowa, but also in Oklahoma and Nebraska.

"The snow is so wet it's sticking to power poles and power lines," said Bill Taylor of the National Weather Service office in North Platte. About 8 inches of snow had fallen in the north-central town of Ainsworth.